1. Field of the Invention
The present invention relates to a recording material detection apparatus configured to detect a surface state of a recording material by irradiating the recording material with light and an image forming apparatus having such a recording material detection apparatus.
2. Description of the Related Art
Image forming apparatuses such as copying machines or laser beam printers are configured to transfer an developer image(toner image) visualized by a developing device on a recording material under predetermined conditions (for example, transfer biases and recording material conveyance speeds at the time of transfer). Then, by heating and pressurizing the recording medium having the developer image transferred thereon under predetermined fixing conditions (for example, fixing temperatures and recording material conveyance speeds at the time of fixing), the developer image is fixed to the recording material.
There is an image forming apparatus including a recording material detecting unit configured to irradiate a recording material with light from a light source and detect a surface state of the recording medium, and configured to determine the types of recording materials on the basis of the result of detection of the recording material detecting unit and control the transferring conditions and fixing conditions.
Such a recording material detecting unit is capable of detecting the recording material stably by controlling the conditions of detection of the recording materials via an adjustment for achieving irradiation with a stable amount of the light from the light source and a shading correction for correcting unevenness of amount of light on the surface of the recording material. More specifically, the amount-of-light adjustment of the light source and the shading correction are enabled by irradiating a reference panel (white reference) with the light from the light source and detecting reflected light therefrom.
Now, Japanese Patent Laid-Open No. 1-099187 discloses a configuration of a reference panel in which the reference panel is movably arranged on the side of a light-receiving unit with respect to the surface of the recording material (in a unit) and is moved to a reading position when needed in order to avoid the dirt or scratches on the reference panel due to the recording materials being conveyed or dust existing in the periphery thereof.
However, with the reference panel having a movable configuration, the mechanism becomes complicated correspondingly, and an increase in the size of the apparatus and a cost increase are resulted.